Diagnostics of density fields in hypersonic flows around a cone in a light-gas gun by the shadow photometric method

A novel approach to obtaining hypersonic flows is proposed and the results of experimental study of hypersonic flows around cones with semivertex angles $\tau_{1}$ = 3$^\circ$ и $\tau_{2}$ = 12$^\circ$ and inflow Mach numbers M = 18 ($\tau_{1}$ = 3$^\circ$) и 14.4 ($\tau_{2}$ = 12$^\circ$) are presented. The use of a light-gas gun where a de Laval nozzle is mounted instead of an acceleration channel allows obtaining a hypersonic flow with a high value of optical density of the outflowing gas sufficient for visualization and diagnostics of the flow by optical methods. The flow pattern is visualized by the shadow method. Shadow images are registered using a high-speed Photron Fastcam camera with an exposure time of 1$\mu$s and frame rate of 300 000 fps. The inflow Mach number is computed using the shadow images based on the angle of shock wave inclination.